The present invention relates to a method of freezing articles in containers.
When freezing articles in containers it is known to use containers in the form of either freezing moulds (from which the articles are removed prior to sale) or packings (which are sold with the article still therein). The freezing moulds are filled with the material to be frozen and are subjected to a cooling, which may be carried out either in a cold space or by treating the freezing moulds outwardly with a cold medium. In cases where the articles are to be frozen in packings, freezing in cold air is usually conducted after the packing has been filled with the material to be frozen.
When the frozen articles are to be removed from the corresponding containers, a superficial thawing operation is carried out. Industrially, this operation may be carried out by briefly subjecting the containers containing the frozen articles to a thawing medium having a temperature which is higher than the melting point of the frozen material concerned, in such that the articles are loosened with respect to the containers or moulds by a thawing of their outer surface, whereinafter the articles may be removed. In cases where the articles in question are frozen in the packings, in which they are to be sold, or in parts thereof, the buyer subjects the packing of the article to a heating effect, e.g., by removing the packed article from the refrigerator, whereinafter the article may be removed from the packing.
During such loosening of the articles in question with respect to the containers in which they have been frozen by thawing, a melting of the outer layer of the articles is caused.
However as a result the articles removed from the containers will not have the exact shape wanted. If, for instance, the thawing operation is carried too far, the material of the article in question may flow, such that the shape of the article is distorted. This is of particular importance when complicated shapes are involved, but it is not without importance even when simple shapes are concerned, i.e., seeing that a flowing of superficial material as referred to above distorts the shape aimed at. The problem is particularly pronounced in cases where the frozen material should be attractive when it is to be served, and the problem referred to is particularly pronounced when the articles are made of ice cream, because such ice cream does not have a well defined melting point and, accordingly, it is necessary to carry out a comparatively effective thawing in order to be sure that the article in question can be removed from the corresponding container.